The IRS reportedly started singling out certain 501(c)(4) groups in 2010 and changed their target several times. Reuters notes that the number of applications sent to the IRS by groups seeking 501(c)(4) status rose to 3,400 in 2012 from 1,500 in 2010.
As Think Tank Watch has previously noted, several prominent think tanks have registered 501(c)(4) entities, also known as "sister organizations," including:
- Heritage Foundation: Heritage Action for America
- Center for American Progress: Center for American Progress Action Fund
- Competitive Enterprise Institute: Freedom Action
- Open Society Foundations: Open Society Policy Center
At this point, there have been no reports that the IRS targeted any think tanks, but the story is only beginning to unfold.
There is a bit of history of the US government going after think tanks. Remember Richard Nixon's plot to break into the Brookings Institution and steal files on Vietnam.